Keppinger was in the lineup as Cincinnati tried for a three-game sweep of the New York Yankees. He batted second and started at shortstop, then moved to third base in the third inning to replace injured Edwin Encarnacion.
Phillips was called up from the minors on May 28. He made two starts at third base for Cincinnati and was batting .143 (3-for-21) with four RBIs. He was hitless in his past 10 at-bats.
The Reds have 10 days to trade, release or send Phillips outright to the minors.